In a Citizens Broadband Radio Service (CBRS) network, Citizens Broadband Radio Service Devices (CBSDs) serve as access points which can support wireless communications with user equipment devices (UEs).
A CBRS network often includes one or more Citizens Broadband Radio Service Devices (CBSDs) with relatively small coverage areas as compared to a macro base station or access point. The CBSDs are used to provide services to subscribers' user equipment devices. Spectrum is granted to each of the CBSDs using a centralized system called the Spectrum Access System (SAS). The Spectrum Access System is a central processing and database system that receives and processes spectrum grant requests. In the CBRS network, interference is managed through power management of CBSD devices by the Spectrum Access System (SAS). The SAS stores information regarding which CBSD uses how much spectrum at which location in the CBRS network. When a specific amount of spectrum is granted to a particular CBSD with a specific transmission power, the SAS calculates the coverage of this CBSD by using a pre-determined path-loss model. Each SAS provider is free to use a path-loss model that fits itself the best, therefore there is at least 7-10 dB in calculated coverage using different path-loss models. There is currently a technological problem in how to accurately estimate a CBSD's coverage and thereby efficiently allocate resources, e.g., power transmission allocations, that efficiently and effectively utilize the limited frequency spectrum available to the CBRS network. The SAS uses crude power transmission level adjustments to increase the overall efficiency of the use of the CBRS frequency spectrum. While the SAS sends CBSDs transmit power change commands it does not manage how or the timing of implementation of the transmit power changes by the CBSD receiving the commands. The SAS power transmission level change commands to CBSD devices can result in disruptions to large numbers of UEs being serviced by the CBSD and/or the quality of service being provided to the UEs as the CBSD is instructed to change, e.g., decrease its power transmission levels if the transmit power level changes are implemented all at once. If the transmit power change is a significant reduction in transmission power a large number of user equipment devices can be dropped or have their quality of service impacted in such a manner as it appears as if the CBRS network is experiencing a failure. With respect to increases in a CBSD's transmission power level when multiple CBSDs in a cluster or with overlapping coverage areas receive a command to increase transmission power at the same or about the same time, if all CBSDs increase their transmit power by a large amount it can result in unanticipated interference across the CBSDs coverage area once again negatively affecting users of UEs being serviced by the CBSDs and quality of service they are receiving. A large increase in transmission power of a CBSD in a single step can also lead a large number of UE devices coming within coverage range of the CBSD and flooding the CBSD with registration and/or service requests. Furthermore, when multiple CBSDs with overlapping coverage both increase their transmission power levels the UEs within the overlapping coverage can enter into race conditions as to which CBSD the UEs should attach to causing unnecessary wireless traffic and potentially causing unnecessary processing of messages at the CBSDs.
From the above it should be understood that there is a need for new and/or improved methods and apparatus for managing a Citizens Broadband Radio Service Device's transmission power level so that the affect on the quality of service and number of user equipment devices that can be serviced is minimized. Additionally, there is a need for new and/or improved methods and apparatus for efficiently managing CBSD power transmission levels to reduce electromagnetic interference while optimizing the CBSD device's coverage area through the gradual increase or reduction of the CBSD's power transmission levels.